Purpose :
Betadine is instilled topically on the eye prior to most ocular surgical procedures to decrease the risk of endophthalmitis. Its effects on vision and the cornea have not been determined. The purpose of this study is to evaluate the effects of Betadine® 5% sterile ophthalmic prep solution (Alcon, Fort Worth, TX) on vision (function) and corneal integrity (structure) in rabbits.

Methods :
Twenty-four female Dutch-Belted rabbits with normal vision were included in this study (Mean age: 2.5 ± 0.94 yrs), divided in two groups: vision group (n=18) and structure group (n=6). The study eye in each group was randomized and was treated with a drop of tetracaine hydrochloride ophthalmic solution USP 0.5% (Bausch and Lomb, Tampa, FL) for topical anesthesia, then with 50 μl of Betadine. Betadine was washed out with sterile saline after 2 mins of exposure. Monocular visual acuities (VA) and corneal fluorescein staining (CFS) were measured at baseline and at 1, 4 and 24 hours post treatment in conscious rabbits. OptoMotor™ system (Prusky et al, 2004; Douglas et al, 2005) was used to collect VA (spatial thresholds) and the total number of punctate stains were used to grade CFS. The effect of Betadine on vision and cornea was evaluated as a function of change from the baseline. The data is presented in the form of mean ± SD.

Results :
The data were analyzed with an ANOVA for multiple comparisons. Mean baseline VA and CFS was respectively 0.789 ± 0.017 cpd and 3 ± 0.8 total punctate stains in the study eye. The VA was significantly reduced post betadine dosing at each follow up time point (0.470 ± 0.17, 0.511 ± 0.17 and 0.609 ± 0.19 respectively at 1, 4 and 24 hrs; p < 0.0001). Total CFS was significantly increased from baseline at each follow up time point (80 ± 4.4, 72 ± 10 and 43 ± 5.1 respectively at 1, 4 and 24 hrs; p < 0.0001). Two thirds of the animals had conjunctival hyperemia and/or blepharospasm up to 24 hrs post Betadine application.

Conclusions :
There was a decrease in VA and an increase in corneal staining that lasted for 24 hours after 5% betadine instillation. The central corneal staining cleared more rapidly than the peripheral cornea. This may have resulted from pooling of Betadine at the limbus and lid margins.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.